Casting



Oct. 15, 1929.

G. M. HOLLENBACK CASTING Filed Feb. 2v, 192e I 2 Sheets-Sheet INVENTOR.

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l Oct. 15, 1929. M, HQLLENBACK 1,731,573

CASTING l Filed Feb. 27, 1928 2 sheets-sheet 2 IN VEN TOR. ewe IZ.HZZenbac/.

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Patented Oct. 15, 1929 UNITE stares PATENT oFFlcs GEORGE M. HOLLENBACK,OF `LOS ANGELES, CALIFORNIA CASTING Application led February 27, 1928.Serial No. 257,520.

movably mounted inv the stems, may on its contact with the mold, actuatethrough any Vsuitable means an automatic lpressure valve to admit thepressure to themold as soon as the pressure head is in firm contacttherewith. 'For many purposes it .is also desirableto have the pressurehead automatically kraised, or withdrawn, as soon as the castingpressure is relieved and a releasing spring may for this purpose act inconnection with` the closing ,piston or other pneumatic device whichmoves the pressure head down upon or into other 25 cooperativeengagementwith the mold;

In the accompanying;l drawings, showing in a somewhat diagrammatic wayan illustrative embodiment of this invention,

1 is a side elevation;

Fig. 2 is a top view; l l

Fig. 3 is anV enlarged vertical section taken substantially along theline 3-3 `of Fig. 2;

Fig.` 4 is an 'enlarged section taken at righi angles to Fig. 3, and

Fig. 5 is a horizontal section taken substantially along the line 5 5 ofFig. n

In the form of' casting apparatus which is particularly adapted forrelatively small dental castings, the different parts of the device maybe conveniently mounted on a suitable casing or support of castviron orother convenient material, which may be formed with a pressure chamber 1to which compressed air may be admitted by the supply line 44, 42whenever the supply valve 34 is opened. See Figs. 1 and 2. Tf desired asuitable pressure gauge 33 may be connected with this chamber'communicating with its interior by the hole 5 shown in Fig. 4. Theairline 43 as shown in Fig. 1 passes into the casing 2 as shown in Fig. 4,and has a closing valve 15 actuated by the handle or knob 32 shown inFig. 1, so that it can be manually moved into the on and od positions.The upper extension 14 of this air line communicates through thepassages 16, 17 with the closing cylinder 7, which may be formedintegral with or forced into or otherwise united with the casing in anydesired way so as to properly support the closing 1 piston 10, whichpreferably has the releasing spring 12 beneath it so as to normallyexert a raising action on this pistonin connection with the cylinder end8. This piston is provided with the connecting rod 11 bolted erotherwise secured to the lower yoke 13, to which several stems such as39, 40 may be bolted or secured, to have vertical movement within thecasing and thus operate the pressure head which may be secured theretoin.,

any vsuitable way. y

As shown in Fig. 3, the pressure head 20 vmay be loosely mounted on thehead yoke 25, connecting these two stems 39, 40, one of which, such as39, may be made hollow so as to transmit the pressure fiuid from theconnected flexible hose or pipe communicating kwith the pressure chamberk1 and thus carry ,Y

this 'fluid pressure through the cross channel 36 tothe pressure valve23, preferably normallyclosed as by the'spring 26 rand autokmatically.actuated, it being understood, of course, that the outer end of thiscross passage or bore is closed as by the screw block 88. The pressurehead may be formed with -a central or axial passage and with atransverse yoke such as 27 having one or more Vents` or air passages 28therethrough and by. bolting or otherwise securing this web to the stem24 of the pressure valve 23, the

vertical movement of this pressure head when v1t engages the mold 19 maybe utilized to open the pressurefvalve at the proper' time, leakage'ofair being of course prevented by a suitable packing or gasket and by a'lower seal or gasket 21 preferably of asbestos v.so

with an upper melting crucible such as L9 communicating through one ormore small bore passages or sprue holes 50 with the mold chamber 5lproper below, which is of course given the desired sli-ape for thearticle which is to be cast It is also desirable to have the top of thecasing formed with a suitable recess or depression such as 52 which mayserve to locate or center the mold and facilitate the casting operation.ln the use of this apparatus the mold may be put in position and themolten metal pouied into the saine, the surplus metal more orlessfilling the crucible 49, then the actuating handle 32 is operated sothat the pressure head is quickly brought down into firm Contact withthe mold and the casting pressure automati` cally applied through theaction of the pres-l sure head as it engages the mold so that the ingdevice may be applied to the mold in some cases before or after thepnssure head is brought down, which serves to heat these relativelysmall molds and still further in` sure uiiifoiin high-grade castings.For some purposes it is desirable to allow the mold to cool before thepneumatic casting pressure is released and which effects the upwardremoval of the pressure head through the action of the releasing springas previously described.

This invention has been described in connection with a number ofillustrative embodiments, forms, proportions, parts and methods ofoperation and use to the details of which disclosures the invention isnot supposed to be limited because what is claimed to be new and what isdesired to be secured by Letters Patent is set forth in the appendedclaims.

Having thus disclosed y my invention, I claim and desire to secure byLetters Patent: l. The dental casting apparatus comprising a unitarycasing formed with a pressure chamber and with a closing cylinder, aclosing piston operating` in said cylinder and having a releasing springnormally raising the same into released position, a lower yoke and apair of stems having their lower endsconnected with said piston andmounted to move vertically in said casing, a head yoke connected to saidstems, a pressure head loosely mounted on said head yoke, one of saidstems being hollow and communicating with said pressure chamber, anormally closed pressure valve operatively connectedwith said pressurehead to be automatically opened when'said pressure head is forced downinto contact with the mold to thereby put said mold underVv pneumaticcasting pressure.

2. The dental casting apparatus comprising a unitary casing formed witha pressure chamber and with a closing cylinder, a closing pistonoperating in said cylinder and having a releasing spring normallyraising the same into released position, a yokek and a stem connectedwith said piston and mounted to vertically move the said casing, apressure head loosely mounted on said stem and having a seal and acentral perforation, a normally closed pressure valve operativelyconnected with said pressure head to be automatically opened whensaidpressure head is forced down in contact with the mold to thereby putsaid mold under pneumatic casting pressure. y

3. The dental casting apparatus comprisinga unitary casing formed with apressure chamber, and with a closing cylinder, a closing pistonoperating in said cylinder and having a releasing spring normallyraising the same into released position, a lower yoke and a stem havingits lower end connected with said piston and mounted to move verticallyin said casing, a head yoke connected to said stem, a pressure headloosely mounted on said head yoke and having a perforated seal, anormally closed pressure valve operatively connected with said pressurehead, said stemY being` hollow and communicating between the pressurechamber and pressure valve, said pressure valve to be automaticallyopened when said pressure head is forced down into contact with the moldto thereby put said mold under pneumatic casting pressure. The dentalcasting apparatus comprising a casing formed with a pressure chainbe acylinder, a piston operating in said cylinder,

resilient means urging the piston in one direction, a hollow stemconnected with said piston and mounted to move in said casing, apressure head communicating with said pressure chamber through saidhollow stem, a

normally closed pressure valve operativelyVv connected with saidpressure head to be automatically opened when said Apressure head isforced down into contact'with the mold to thereby put said moldunderpneumatic castingpressure.

In testimony whereof, I have signed myV name to this specification. Y

GEORGE M. HOLLENBACK.

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